1. Field of the Invention
The present invention relates to a cartridge that has a chamber for holding a recording material used for recording therein. More specifically the invention pertains to a cartridge with a built-in non-volatile memory and a technique of transmitting information to and from such a cartridge.
2. Description of the Related Art
Recording apparatus that eject inks on printing paper to record images, such as ink jet printers, and recording apparatus that utilize toners for recording have widely been used. A cartridge attached to such a recording apparatus has a chamber for holding a recording material like ink or toner therein. Management of the residual quantity of the recording material is an important technique in the recording apparatus. The recording apparatus counts the consumption of the recording material according to the software program. Data on the residual quantity of the recording material computed from the observed count are stored in a memory of the recording apparatus for the management purpose. The same data may also be stored in a built-in memory of the cartridge.
A non-volatile memory is applicable for the built-in memory of the cartridge. The non-volatile memory enables data, such as the residual quantity of ink, to be kept even after detachment of the cartridge from the recording apparatus. Application of such a memory ensures consistent management of the residual quantity of ink and other data even when the replaced cartridge is attached again to the recording apparatus.
An important issue of such cartridges with the built-in memory is to ensure a sufficiently high reliability in the storage content of the memory. There are two primary causes of lowering the reliability in the storage content of the memory. One cause is an accidental cutoff of the power supply to the recording apparatus in the course of updating data into the cartridge or a careless detachment of the cartridge in the course of updating data. In such cases, it is practically impossible to verify the updated storage content in the memory of the cartridge. The other cause is a failed electrical connection. The cartridge is basically designed to be freely attachable to and detachable from the recording apparatus so that no fixed signal line is usable for connection with the memory in the cartridge. This may cause a loose contact or another failure in electrical connection.
One possible measure carries out the memory updating operation a plurality of times. Another possible measure provides duplicate memories and writes identical data into the duplicate memories. In the case of a loose connection of a signal line, however, these measures do not heighten the reliability. When an electrically erasable semiconductor memory (EEPROM) is applied for the built-in memory of the cartridge, the data rewriting procedure first erases the existing data in the memory and then writes new data into the memory. This requires two normal accesses for erasing and writing data and thus demands a high reliability.